1. Field of the Invention
This invention relates generally to tires and more specifically, materials for forming sidewall supports in a tire and such supports.
2. Description of the Related Art
Tire manufacturers have been developing solutions for how passengers in vehicles having pneumatic tires can continue on their journey for at least some minimum distance upon a tire losing all or substantially all of its pressure. While spare tires are one solution for such a problem, a better solution would allow the passengers to continue without having to get out of their vehicle until reaching a safe destination.
The idea of extended mobility allows a vehicle to continue to drive along on a tire that has lost all or substantially all of its inflation for at least a reasonable distance. Such tires, based on run-flat technology, often include a self-supporting feature that allows the tires to support a significant load at reduced pressure or even no pressure. Such self-supporting feature may include a tire sidewall that is reinforced with rubber inserts as shown, for example, in U.S. Pat. No. 6,022,434, which is hereby fully incorporated by reference.
Because the rubber inserts have to be able to support the load of the vehicle at a reduced or no inflation pressure, these inserts are often quite thick and they typically impact the rolling resistance characteristics of the tire. Researchers in the tire industry are searching for new materials and new designs for such sidewall supports to improve the rolling resistance of such tires and their durability when operated under no or little pressure.